Solving four trigonometric equations, four unknowns
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Please I want to solve these four trigonometric equations, four unknowns using a matlab code
10 cos ∅3 + 10 cos ∅2 − 𝑟1 = 0
15 cos ∅4 + 12 cos ∅2 − 𝑟1 = 0
10 sin∅3 + 10 sin∅2 = 0
15 sin∅4 + 12 sin∅2 = 0
thank you in advance.
采纳的回答
It seems that only 4 complex solutions exist.
syms phi2 phi3 phi4 r1
eqn1 = 10*cos(phi3)+10*cos(phi2)-r1 == 0;
eqn2 = 15*cos(phi4)+12*cos(phi2)-r1 == 0;
eqn3 = 10*sin(phi3)+10*sin(phi2) == 0;
eqn4 = 15*sin(phi4)+12*sin(phi2) == 0;
sol = solve([eqn1,eqn2,eqn3,eqn4],[phi2 phi3 phi4 r1])
double(sol.phi2)
double(sol.phi3)
double(sol.phi4)
double(sol.r1)
更多回答（1 个）
You can solve symbolically -
syms r1 t2 t3 t4
e1 = 10*cos(t3) + 10*cos(t2) - r1 == 0;
e2 = 15*cos(t4) + 12*cos(t2) - r1 == 0;
e3 = 10*sin(t3) + 10*sin(t2) == 0;
e4 = 15*sin(t4) + 12*sin(t2) == 0;
y=solve([e1 e2 e3 e4],[r1 t2 t3 t4])
y.r1
y.t2
Use double() to get numeric values
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